﻿     var code ; //在全局 定义验证码   
     function createCode()   
     {    
       code = "";   
       var codeLength = 3;//验证码的长度   
       var checkCode = document.getElementById("codecode");   
       var selectChar = new Array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');//所有候选组成验证码的字符，当然也可以用中文的   
           
       for(var i=0;i<codeLength;i++)   
       {   
         
           
       var charIndex = Math.floor(Math.random()*26);   
       code +=selectChar[charIndex];   
          
          
       }   
       //alert(code);   
       if(checkCode)   
       {   
         checkCode.className="code";   
         checkCode.value = code;   
         //checkCode.innerHTML= "sdlakfjalksjf";     
           document.getElementById("codealert").value="→更新验证码";
       }   
          
     }   
        
function validate()   
{   

       var inputCode = document.getElementById("validatecode").value;   
       if(inputCode.length <=0)   
       {   
           document.getElementById("codealert").value="请输入验证码";
           document.getElementById("validatecode").value="";
       }   
       else if(inputCode != code)   
       {   
          document.getElementById("codealert").value="×验证码错误";
           document.getElementById("validatecode").value="";
          createCode();//刷新验证码   
       }   
       else
       {
          document.getElementById("codealert").value="√验证码正确";
        }
}   
